The Physician
by BlueNeutrino
Summary: After being cured of being a demon and with concerns about lasting damage and how the Mark is affecting his health, Dean visits a mysterious doctor who he thinks can help. Gen. Set early season 10.
1. I

**A/N: Originally written because I was having a crappy week and just wanted to indulge myself, though I hope other people may derive entertainment from this. Posted initially on Tumblr and AO3, and due to a good response, now posted here. Set around early season 10, post 10x03.**

 **Disclaimer: This is the only site I do these on purely for the sake of tradition. I don't own Supernatural.**

 _ **The Physician**_

Dean's knuckles rap sharply on the plain white door; the sound unnaturally loud in the disconcerting stillness. His eyes flicker around shiftily, glancing back down the stairwell and then scowling at the elevator with red tape tied across the grill. It had taken him to the 36th floor, but an unspecified fault had left him to take the remaining three on his own, leading him to the single loft at the very top of the building.

The ensuing silence drags out long enough for another wave of anxiety to perturb him. Should he have come? Did Sam buy his excuse? Not for the first time, the thought crosses his mind, feeling the familiar guilt at lying to his brother. _Should I just have gone to Cas? Maybe I don't have to…_ There isn't quite enough time for him to fully consider walking away before he hears a voice from the other side: cold, female, British. Now he's committed.

"Who is it?"

The voice is harsh, demanding, and already Dean knows he's being scrutinized through the peephole. Mouth dry, he clears his throat before answering, "I, uh…I'm looking for Dr Carter."

"Not what I asked." The response is blunt, and he blinks. If he hadn't known what to expect before, he's even less certain now.

"My name's Dean Winchester."

Whether it was a good idea to tell the truth or not, it gets results. He hears the sound of a deadbolt being drawn back, and then the door opens a crack. Through the gap, Dean can see a woman eyeing him suspiciously, sharp eyes the color of steel. "What do you want with Dr Carter?"

From what he can see in the dim light, he'd guess she's in her early forties. Pale skin. Black hair drastically mismatched on either side of her face, like an undercut sloppily growing out. Sharp jawline. Freckles. The arm holding the door open has multiple puncture marks on the inside elbow, blossoming into a purplish-come-yellow bruise. All things considered, he really doesn't know what to make of that.

"Uh…" Dean licks his lips. "Medical advice."

There's a pause, and then she asks, "Can you pay?"

His only response is to reach into his jacket and take out the wad of bills to wave at her, which seems to satisfy. "Alright." She opens the door wider and stands aside, a sharp jerk of her head telling him to go in.

Nervously, he does, stepping past the threshold to view the apartment beyond. It's uninvitingly minimalist, to say the least. Grey carpet, two worn black leather couches in the central space surrounding a glass coffee table, and not much else. He expects there's more in the other rooms, although from what he can tell, the loft isn't divided into rooms so much as just partitions. Two floor-to-ceiling dividers break up the space he's standing in, enough to for him to see there are gaps instead of doorways, although he can't see enough to tell what's on the other side. Opposite the entrance, a huge window leading onto a narrow balcony takes up most of the wall. This is far from the tallest building in the city, but he could be on the twelfth floor or the eightieth for all Dean can see, the floors of neighbouring skyscrapers in both directions soon becoming lost to the fog. It doesn't seem to him that the interior of the apartment is much warmer than the outside, and he shivers.

"Alright, what can I help you with?" the woman asks as she shuts the door and bolts it, her tone cold and not sounding at all helpful. She strides past him to sit down on the couch facing away from the window, fixing him with a stare as if expecting him to sit opposite.

He blinks again. "You're Dr Carter?"

"No, I'm the fucking maid," she snaps back, and he actually feels a little cowed. Coming here is starting to seem more and more like a bad idea.

She seems to notice his discomfort and sighs, rolling her eyes before her expression softens just slightly. "Yes, I'm Dr Carter. Please, take a seat and tell me how I can help you."

The forced friendliness doesn't exactly put Dean at ease, but awkwardly, he crosses to the couch and sits down. "Right. I, uh… I know you're a doctor. For demons."

"Which you aren't," she states bluntly, one eyebrow raised as she casts a cool glance over him. It only makes him more nervous, and he shifts uncomfortably in his seat, trying to avoid eye contact.

"No, but I was. I know you helps demons with damaged vessels, so I was wondering…"

"There's a cure for being a demon now?" she suddenly interjects, and he stumbles over his words. This should not be so unnerving.

"Uh…yeah. We found a ritual that does it. My brother cured me by injecting me with purified blood, but…the whole thing wasn't exactly smooth sailing. I'm worried there's been some lasting damage."

That's when he dares try to look her in the eye again, and feels another shiver runs down his spine as he sees her leaning forward in her seat with cold eyes boring into him. "Interesting," she remarks. "What kind of damage?"

"I don't know, but…I think my heart. I keep getting palpitations. Sometimes bad dreams, and I'll wake up with my heart pounding so hard it hurts." As if on cue, he can feel his pulse picking up, the Mark on his arm giving a twinge. He doesn't know yet if it's a good idea to mention that or not.

Now she leans back in her seat, a thoughtful expression on her face, and he isn't sure if that's better or worse than what she was doing before. "And you think I could do something to help you?"

He swallows. "Yes."

"Hmm. Well, I can't say I've ever dealt with a cured demon before, but you've intrigued me. I can certainly take a look at you, if that's what you want? Then we'll see about any treatments."

He knows that's what he came for. That's exactly what he came for, but now that he's here facing her, he's more nervous than ever. "Yeah, that's what I was hoping."

With no further preamble, she stands up. "Alright. This way."

Taken aback by just how quickly things are moving, but also with a strange feeling like she's just given an order that he has to obey, Dean gets up and follows.


	2. II

She leads him around one of the partition walls through a small kitchenette – as sparsely furnished as the living room – and then round a corner towards where a translucent plastic curtain hangs from ceiling to floor. Dean raises an eyebrow as she pulls back one of the plastic strips to allow him through, the room beyond seeming to him to better befit an industrial warehouse than a medical setting. There are no windows, the room bordered on two sides by plywood partitions and on the other two by cold grey brick, with the plastic sheet forming the only entrance. The gloom lifts slightly when Carter crosses to the wall to flick on a light switch, but the only light source is a single, dim yellow lightbulb hanging by a cable from the ceiling. A plain wooden chair sits just to the right of the entrance and the scent of disinfectant hangs thick in the air. Dean spies a mop and bucket propped against one of the brick walls, beside it a couple of trolleys laden with instruments plus a medical lamp, but what immediately catches his eye is the apparent centrepiece of the room: a single exam table, relatively new looking and upholstered in black vinyl to match the floor. His mouth goes dry when he notices the leather restraints attached.

A chuckle sounds off to his left as Carter notices where he's looking. "Don't worry, I'm not going to be using those today. Unless you're into that."

He scowls as he glances back at her, unable to tell if that was meant to be banter or if she's just mocking him. Either way, it doesn't exactly put him at ease. "I think I'll pass."

She just shrugs. "Can I take your jacket?"

Taken aback, he slips it off and hands it her, for a moment thinking maybe she's actually trying to be polite. Then he sees her not-at-all subtly check out the cash he's put back in the inside pocket.

"Alright, shirt off," she orders, casually draping his jacket over the back of the chair by the door and then crossing to one of the trolleys to wheel it over. "On the exam table, if you don't mind."

Dean can already feel goosebumps forming on his arms, the air in here seeming even colder than the rest of the apartment, but he'll be damned if he says anything. Obediently, he slips off his flannel and t-shirt, and she takes them off him to dump by his jacket as he sits down on the side of the table. His gaze wanders over to the cart she's just rolled across, and aside from the regular equipment like the thermometer and stethoscope lying there, he can't help but notice the tray of surgical instruments beside it. He gets no such reassurance that she isn't planning on using those.

"Alright," Carter finally says, picking up the stethoscope to sling round her neck and snapping on some latex gloves. "Let's get this show on the road, and all that." She gives him no warning of what she's about to do, and the next thing he knows a penlight is in her hand and she's shining it in his eyes. It's unexpected, and he blinks, earning him a cold hand on his forehead and a thumb holding his eyelid open. She doesn't say a word.

He's silent for a couple of seconds as the light moves from side to side, then his curiosity gets the better of him. "I thought you were checking my heart?"

"You said you were a demon," she says, shifting over to his other eye. "I just want to check all bases."

 _Oh._ He can't bring himself to respond to that, scared that if he asks if there's any black in his eyes, the answer might actually be yes. Fortunately, it seems that everything's kosher as she straightens up without comment, putting the penlight down and then picking up another instrument. "Gonna do a blood test too. I want to check your sulfur levels."

Warily, he eyes the syringe and tourniquet she's holding in her hands. Last time he'd been anywhere near a needle, it was Sam injecting him with purified blood to try and purge the demon from him. It's done nothing to make him hate needles any less.

He takes just a second too long in straightening his arm for her, so she does it for him, grabbing his left wrist and roughly pulling to expose the inside of his elbow. He scowls, and despite his discomfort he can't bite his tongue. "What happened to medicine needing a gentle touch?"

He's expecting an equally scathing retort, but her response surprises him. "Sorry, I'm used to dealing with patients that require a bit of rough handling."

That only prompts more questions about what treating demons even involves, but they don't reach his lips before his eyes land on the puncture marks on her own arm again. Tightening the tourniquet around his bicep, she again notices where he's looking. "Don't worry. I've got better aim than it looks."

"Hm." One eyebrow creeps closer to his hairline. "So…you one of those Gregory House types? Drug addict with a brilliant medical mind?"

It's a bold question, especially with the hint of sarcasm, but rather than looking pissed she gives a wry smile. "It's not drugs. Let's call it…on ongoing experiment in organic alchemy."

"Alchemy?"

"Yeah." Her probing fingers find a suitable vein, and she swabs the area with alcohol before prepping the needle. "The application of alchemy to medicine. That's my field."

"And that lends itself to treating demons?" He asks the question then immediately winces as the needle punctures his skin. Hopefully, that wasn't intended as more rough handling.

"Demons make great guinea pigs. You've got a body you can do just about anything to and they'll still be lucid enough to answer questions."

Now that strikes a nerve. He hadn't exactly been expecting to find anyone with anything other than firmly grey morals when he came here, but hearing her say it leaves a bitter taste in his mouth. "Doesn't it bother you there's an actual person in there being possessed? Who's suffering because of the demon you're trying to help?" He doesn't care if that pisses her off. He knows he needs her help. Doesn't mean he has to like it.

Cold eyes settle on him once again as he feels a twinge from the needle in his arm, and he wonders if she just jabbed it deeper deliberately. "Trust me. By the time they get to me, anyone else in that vessel is long gone. The whole reason demons seek my help is that their vessels have passed the point of being able to function like something living."

Whether that makes it better or not, he really doesn't know. In any case, antagonizing her doesn't seem like a good move right now. Exhaling slowly, he says no more and lets his eyes fall to the vial now filling with his blood: a surprisingly fast gush from his vein that forms bubbles as it hits the sides of the tube. It's not exactly pleasant, and he grimaces.

Just a few seconds later, and she's pulling the needle out and pressing a cotton bud to the inside of his arm. "All done. Keep the pressure on that for a sec." He obeys, watching her rip off a strip of tape to secure the dressing in place, and then she shoots him another question. "You cold?"

That takes him by surprise. "What? No, I'm fine."

"Your skin says you're cold." Apparently, she's just noticed his goosebumps.

"No, really. I'm okay."

"I have a thermostat. I can turn it on if you like."

"I guess…" Now he narrows his eyes in confusion, watching her head to the wall to turn on the heating. "Aren't _you_ cold?"

"I don't get cold," she states plainly, crossing back to him without even glancing at his face. That only raises more questions, but right now, he doesn't feel inclined to ask. "Right. Gonna take your pulse. Give me your right arm."

Now's the part where he knows he can't hide the Mark from her, if she somehow hasn't noticed it already. Somewhat hesitantly, he extends his right arm for her, but she digs her fingers into the artery below his thumb and looks at her watch without comment. "Ninety-six beats per minute," she remarks after what Dean's sure can't have been a full sixty seconds. "Nervous, Winchester?"

Again, he can't tell if she's mocking him or not. "Well, your bedside manner could use a little work."

She chuckles. "That's what they said in med school. I mean, I wanted to be a coroner. Never thought it would be an issue."

The statement is far from reassuring, and an uncomfortable thought springs to mind. "Wait…if you've been treating demons that are mostly just dead meatsuits, when was the last time you actually treated someone living?"

"You're asking me to think back a long way, there."

He's sure his pulse thumps a little faster at the words. "So…not many beating hearts?"

"No, actually. This is quite a nice novelty."

An uncomfortable feeling settles in the pit of his stomach, and he finds he's fighting the urge to just get the hell away from here. There's not been a single thing she's done or said since his arrival that has put him at ease.

"Seriously, Dean," she says when she realises he's too caught up in his own thoughts to say anything more. "Ninety-six bpm is an unusually high resting rate. I need to know if it's because of nerves, or something else."

He turns his head to look at her, gritting his teeth when he has to meet her gaze. His reply is cold. "I'm nervous, I think."

There's no change in her expression. "Alright," she says simply, dropping his wrist and crossing to the cart to pick up another instrument. "I'll do your blood pressure then." Her head jerks sharply towards his arm as she brings the cuff back over to him and unslings the stethoscope from her neck. That's when the bombshell drops. "You gonna tell me about that, or just assume I'm an idiot who hasn't noticed?"


	3. III

Immediately, heat floods Dean's face. Now his heart is _definitely_ beating faster. "Oh, that. That's, uh…" He glances down at the Mark on his forearm, wondering how to explain it, but then she comes to stand directly in front of him and leans in closer to his face.

"Look, Dean," she says, her tone firm but her expression softer than expected. "I don't like people knowing my business, so I make a point of not asking other people theirs, but if you want my help, and it's medically relevant, I need to know what that is. Just tell it to me straight."

"Right." He swallows. Best to just bite the bullet then. "It's the Mark of Cain."

There's a pause, and he's surprised by the complete indifference in her expression. "From the Bible?"

"Yes. I got the Mark so I could kill this demon, Abaddon, who wanted to take over Hell. Then I died, but the Mark brought me back. As a demon."

"And your brother cured you?"

"Yes."

"And you think the Mark's been affecting your health?"

"Yes."

"Got it."

He blinks, surprised by how straightforward that was. "You don't want to know anything else?"

"Not for now. I'm just concerned with what your body's gonna tell me. If I need context, I'll ask."

 _Well that's…_ Dean doesn't even know what that is. He just stays silent as she slips the cuff onto his bicep and fits the stethoscope in her ears, gripping the bulb as she begins to inflate it. It pinches uncomfortably, but a short while later and she's finished, pulling it off of his arm again. "120 over 80. Upper end of acceptable."

He watches her as she puts the sphygmomanometer back on the trolley. "So…what are you thinking so far? Anything wrong with me?"

"The only thing I can tell that's wrong with you so far is that you're nervous. But that's understandable." She shoots him a smirk as she comes to stand back in front of him, twirling the end of the stethoscope in her hands. "I'll be able to tell a lot more once I've actually listened to your heart."

Dean's not sure why, but he's suddenly feeling incredibly exposed and vulnerable under the force of her stare. Something in her eyes just seems…over-eager, lingering on his bare chest as if she could stare right through to his heart. Maybe it's just diligence, but it makes him shift uncomfortably.

She doesn't give him any warning again when the end of the stethoscope hits his chest, and he hisses from how cold it is. While the air seems to have marginally warmed since she turned on the heating, the metal diaphragm is still like ice. "Sorry," she says drily, not at all seeming like she means it when she pulls back the chestpiece to blow on it then returns it to his skin. He can't honestly say that it's helped.

There's a few moments in which he dutifully remains silent, allowing her to listen. He doesn't know for sure what she's hearing, but he can hazard a guess: his heart thumping a fraction too fast, the occasionally skipped beat disrupting its rhythm. It feels heavy in his chest, like the only thing supporting its weight are the butterflies trying to rise up from his stomach. The Mark on his arm throbs again.

"I'm just gonna check your lungs," she announces suddenly, although he can't tell from her expression if she's heard anything worrying or not. She moves round the back of the table and then the next thing he knows is the fractionally warmer touch of the stethoscope on his back. It's somewhat perturbing to not have her in his line of sight, but he fights down his unease and tries to obey her instructions to breathe deeply.

A few more seconds pass until she asks another question. "You got any history of heart trouble? Prior to the demon thing."

"I, uh…" He hesitates, unsure what to say. "Can I talk?"

"I'm listening while you talk, that's the point. Answer the question."

He bristles slightly at her tone, but clears his throat, wondering what it sounds like to her. "Kinda. I don't know how relevant it is though."

Unexpectedly, the stethoscope leaves his skin and a moment later she's crossed back round in front of him, wearing an irritated scowl. "What do you mean 'kinda'? It's a simple enough question. Just tell me whatever heart history you have."

"I had a heart attack about ten years ago."

"That would be relevant." He resents the patronising look that accompanies it.

"Yeah, but in the meantime, I died and got brought back to life by an angel. I think that pretty much gave me a master reset."

She quirks an eyebrow, and he can tell she's surprised. "Angel?"

"Yeah, they're real. Kinda go hand in hand with demons."

She scowls harder, and it satisfies him to know she doesn't like her own attitude being thrown right back at her. "How many times have you died?"

"You want a number?"

There's a pause. She takes a moment to consider, then decides she doesn't care. "Actually, no. Lie down. I need to palpate your heart."

He does as he's told, but is curious what's coming as she takes off the stethoscope and slings it back around her neck. "I hope that's not an invasive procedure or anything."

"It's a nice way of saying I'm gonna start prodding and poking your chest. Now lie still."

He's barely got in position when he feels a cold, gloved hand lie flat across his sternum. She pushes in with the heel of her hand briefly and then starts to move across his chest, taking no care to be gentle.

As her fingers press between his ribs, countering the pressure from the heavy thumping of his heart, Dean feels a sudden, momentary heat flare up beneath her touch. Red sweeps over his vision and a stabbing pain shoots up from the Mark to his chest. Then, just as suddenly as it appeared, it's gone.

She notices the stutter in his heartbeat, the way his breathing has suddenly become heavy, panicked. "Everything okay?"

"Yeah, I…" He says it instinctively, although he knows it's futile to try and lie. "I don't know. My chest, just…hurt for a moment."

A pensive look passes over her face. "Here," she says, and he glances down to where she has two fingers pressed to the center of his chest. The hard, jabbing pressure feels all too familiar. "I heard a murmur over this spot. Can still feel it now. It's as though there's been…damage."

Somewhat nervously, Dean swallows. Just for a moment, he closes his eyes and tilts his head back to rest on the table, drawing a calming breath. "It's where I was stabbed."

"Hmm." She makes a thoughtful noise, but when he looks up again her expression is as impassive as ever. "That what killed you? Prior to becoming a demon." She's taking this all unexpectedly in her stride.

"Yeah."

"Alright. I just want to try something, Dean." She turns away from him and goes to fetch the second trolley of instruments from by the wall, the one with monitoring equipment and oxygen tanks. He's curious, and more than a little concerned at how serious she thinks this is, though he can't read a damn thing from her face. His heart's begun thumping even harder, each beat starting to feel like a punch inside his chest. It's making him nauseous.

"I need to get a closer look at your heart," she elaborates, and then he's watching her prep another needle, filling it with a clear fluid. The tray of surgical instruments is still conspicuously close by. "There's definitely something I can't…" Dean doesn't hear a word of anything else she says, drowned out by the pounding of the blood in his ears. The red has returned to his vision, pulsing at the edges with each throb of his heart. He knows he should say something, but his tongue feels too heavy, his lungs too tight. All he can feel is the growing heat simmering beneath his skin, in his muscles, in his blood…

He can't wonder what's happening when he can't even think straight.

When she turns back to him, needle in hand, passing just inches from a glinting scalpel that dazzles him more than it should in the dim light, the next thing he knows is his own hand has reached out to close round her wrist. There's a pause, a moment of shock that passes in a fleeting heartbeat, and then Dean's leaping up from the table. He isn't thinking, moving on autopilot as his other hand grasps for the offending scalpel and moves to slash at her face.

To his surprise, or what would have been his surprise had he any lucidity left, he never draws blood. Her own hand rises in an instant, closing tightly around his wrist, and it's as if he's been stopped with the solidity of an iron wall. She fixes him with a piercing stare, surprise mixed with what could almost be annoyance, and then her other hand moves to break free of his grip.

What happens next is a blur. Dean sees the needle jabbing towards his neck, and instinctively he raises his fist to knock the syringe from her hands. He barrels forward into the opening, throwing her off balance as he breaks her grip on his wrist. The scalpel slashes again. This time it draws a shallow cut up the side of her cheek, and angered, her eyes widen.

He doesn't have chance to think, to regain control, to process anything before she's suddenly lunging forward to try to wrestle the scalpel from him. Both hands grasp for the weapon while she lands a solid kick to his kneecap, and he falls, colliding roughly with one of the trolleys. Instruments go flying as it topples, colliding with the other one and sending equipment hurtling to the floor with a deafening crash. A canister of gas falls and begins to roll away, emitting a soft hiss.

Dean doesn't register the pain shooting up his side, doesn't register anything but the craving burning hot in his veins, a desire he can't even define but knows he needs to satisfy. His heart continues to race, and somewhere between beats he's on his feet again, throwing himself towards her. She never has chance to use the scalpel before they both end up back on the floor.

Winded, she gasps, trying to scramble out from under him, but his hands close around her throat before she can draw a breath. Somewhere in the back of Dean's mind there's a voice: a distant, annoying, persistent voice that might be screaming something along the lines of "Stop," but he can't really hear.

He stares down at her, rage burning in his eyes as he waits for the lights so go out, but while she fixes him with a cold glare, she isn't struggling. The gas tank rolls by her head as her hands scrabble for something he doesn't even care to look at, and then, unexpectedly, she slams her forehead hard into his nose. Against all strength he thought he had, he feels a sudden punch to his jaw as she succeeds in throwing him off.

Less than a heartbeat passes before he collects himself, rushing back at her before she can gain the upper hand. Amongst the scattered instruments on the floor his hands scramble for a weapon, by chance landing on a pair of rib cutters and mindlessly stabbing towards her head. She blocks it, and for several heartbeats they struggle, messy, frantic as her hands claw at his face and he fights to pin her down. For a moment it seems like he's succeeded, until she hooks her leg beneath his knee and rolls, throwing him with surprising force to the floor.

The weapon is wrenched from his hands as he's left lying face down on the vinyl, chest heaving, feeling the weight of her lying awkwardly on top of him. She isn't heavy enough to pin him, and almost instantly he retaliates, trying to roll to slam her down hard onto her back. It proves to be a mistake.

The minute she lands he feels her arm close around his neck in a chokehold, pressure tightening across his carotid arteries. He struggles, almost surprised by the strength with which she's holding him, but a heartbeat later and he feels a mask being held over his face. There's a hiss, a sharp, acetic smell floods his nostrils, and the strength begins to seep from his muscles. The gas tank rolls past again as he begins to grow weak.

There's a moment of horrified panic for him to realize what he's done before the red fades from his vision and is replaced with black.


	4. IV

Dean comes around slowly. The persistent ache behind his eyes makes itself known before anything else, followed shortly by the dull throbbing in his arm. It ebbs in time with his pulse, the Mark still asserting its presence, but now it's more discomfort than pain. He groans softly as he eases his eyes open. Above him, the lone lightbulb from earlier immediately makes him squint, and a turn of his head tells him he's back on the exam table.

The equipment carts are back upright, everything returned to its rightful place. There's an intermittent beeping coming from one of the monitors, and it takes him a couple of seconds longer to realize the EKG is switched on and its leads are attached to his chest. Blinking to try and clear his head, Dean tries to sit up, but immediately finds a resistance tugging at his wrists and ankles. He glances down at his body and then gives up. Looks like she did have to use the restraints after all.

"Hey."

The voice comes from close by his ear, and he twists his head round to look at the source. Grey eyes stare back. It seems Carter has pulled up the chair from by the door and is sat next to the table, elbow resting next his head and her chin propped up by her hand. She looks almost bored. "You done being all Psycho now?"

"I…" He begins speaking before his mind's truly caught up with the situation. "I'm so sorry…"

"I don't care," she cuts him off disinterestedly. "I just need to know if you're done with all that."

"I…think so." Dean can't be sure. He blinks again, taking another glance down at himself, and realising with a dull note of panic that his belt is unfastened and for whatever reason, she's taken his boots and socks off. "What happened?"

"I put you under; got you on the table; tied you up; put you on the monitor; took a look at your heart with the echo machine; went and analysed that blood sample I took earlier; tidied stuff up in here… It's amazing what you can get done in a couple of hours." She sounds surprisingly nonplussed, although he can still see the red line of the cut down her cheek and feels a jolt of guilt.

"I don't know what came over me. I am sorry…"

"You've said." She genuinely doesn't seem to care. "And I think you do. Know what came over you, I mean." Her pointed glance at the Mark tells him she has it figured out.

"Yeah, I…" He changes direction when he looks down at himself again. "You mind explaining that?"

"Oh. Yeah. I was checking your pulse points. Your radial pulse vanished so I had to make sure. There's a couple of pulse points in your feet and then your femoral artery."

His eyes widen. "Excuse me?"

"Don't worry, I didn't cop a feel. I don't go for that."

"You jumped at the chance to get my pants open."

"Yeah, well. It helps your circulation." She gives him a slightly mocking look. "I'm sorry, does that make you uncomfortable? Because being attacked by someone I'm trying to help makes me uncomfortable."

Suitably admonished, he lets it drop. Tentatively, he tests the straps around his wrists again. "Any chance you could take these off now? I think I've done my Hulking out for the day."

She gives a dry laugh. "Uh, no. I don't think so. Not until I'm sure you won't go off the rails again."

"I'm feeling calmer."

"Your heart rate's still as high as it was before you flipped out the first time." She nods towards the monitor, where he can see his heart's still beating more than eighty times a minute. As if he couldn't feel it anyway. "I'd rather not get into another scrap. I've only just got everything tidied up."

"You know, you're stronger than you look."

"So are you." He doesn't know what kind of look he gives her in response to that until she chuckles. "That wasn't meant as an insult. I can kick the shit out of most rowdy demons without breaking a sweat, but you… You put up one hell of a fight."

"Yeah, well… I've got this thing supercharging me." He lifts his right arm until it's stopped by the restraints. "What's your excuse?"

"I've already told you, if you've been paying attention."

He thinks for a moment. "What was it? 'An ongoing experiment in organic alchemy'?"

She gives him a condescending smile. "Clever boy."

Once again, her attitude grates on him. "Alright, so…how long until I can get out of here?"

She doesn't answer immediately. Instead, she gets up and crosses round the table until she's standing on his right hand side, observing the monitor screen. "That all rather depends. Guy your age, in good shape…your resting heart rate should be in the sixties. It hasn't dropped below eighty since you got here. And until it does…I don't know that you aren't gonna go all crazy violent on me again."

This is starting to get frustrating. He balls his fists and then flexes them as he lets out a steady breath, trying to ease the tension building in his chest. It's a fight not to get angry. "Yeah, well. You were about to inject me with a needle full of you-didn't-say-what and you're keeping a tray of surgical tools right next to me. That may have been a trigger point."

It's not quite an outburst, but it gets her attention. She turns to fix him with a cool stare. "I'm working out of an unfinished loft conversion with two equipment carts and one room I can keep sterile. Cut me some slack. It's not like I don't end up using them 90% of the time. In case you've forgotten, you're not my usual clientele."

"Well, an explanation would still have been nice."

"Demons don't usually demand that either."

He shoots her a scowl, but getting into an argument isn't likely to get him out of the cuffs faster. Trying to calm down, he gives a huff and closes his eyes. "What was in the needle, then?" he asks after a couple of seconds.

"Contrast agent," she states drily, and when he opens his eyes again he can see she's leaning on the table. "For the echocardiogram."

He gives her a blank look.

"Heart ultrasound," she clarifies with a roll of her eyes. "I was intending to do it while you were still conscious. Still… there's one thing I am curious about." She glances down at his arm, then back up at his face. He's surprised to see most of the hostility has gone from her expression. "Most demons don't even get the power of self-healing. When you were a demon…did you have a heartbeat?"

He's taken aback, but supposes the question makes sense. "I…" Now that he's contemplating it, he isn't sure. "I think so." All he can remember is the way it was pounding as Sam tried to heal him. The rest of the time…if it had been there, it was too slow to notice.

"Hmm. Interesting…" A thoughtful look settles on her face as her eyes lower to his arm, careful and scrutinizing. She reaches out to gently press two fingers to the Mark, almost caressing his skin. "Then I think this is only one of your problems."

He winces, the contact prompting another dull twinge of pain. A heavy weight seems to have settled in the pit of his stomach, though he doesn't know what he'd expected to hear. "Great. This the part where you give me the bad news?"

There's another pause. She glances over at the monitor screen, noting his heart rate has bumped up another notch, and then meets his gaze. He figures she's not one for breaking this to him gently. "There's tissue damage to your heart. Here." She taps over the center of his chest again. "Scar tissue showed up on the echo in the right ventricle, making it stiff and resistant to contraction. Also damage to the valve, causing tricuspid regurgitation. I think you have getting stabbed to thank for that."

Half of those words weren't even English to him, but he gets the gist that it's bad. She doesn't give him chance to ask questions before continuing.

"From the EKG, looks like there's increased electrical permeability in the calcium channels in your heart. My guess is that's down to the demon cure, which should have decreased the sulfur levels in your blood. Maybe by purging, or through chemical reactions to convert it into innocuous compounds, such as calcium sulfate. However, from your bloodwork, you've got increased levels of both calcium and sulfate ions, as well as trace amounts of pure sulfur in your blood, which says to me the Mark's trying to convert you back into a demon and your body's fighting it off. That also seems to explain why the Mark's pushing your body into overdrive. I took your temperature earlier…"

His eyes widen then, glancing down at his conspicuously open belt, and she smirks. " _Orally._ Quit panicking, Winchester. But the point is it shouldn't be 100.2 degrees. You should be running a fever, but you're not. Your body's baseline temperature has been altered, and it's down to this." She taps the Mark again. "Everything's working too hard and too fast. Combine that with the structural damage to your heart, and I'd say the palpitations you've been having have been atrial fibrillation. Your heart wants to beat faster, but the scar tissue's resisting, hence arrhythmias in the atria and the vanishing radial pulse. All that together, and…" She draws a breath. "It's gonna burn you out."

Most of it was babble to him, but that final line made perfect sense. His stomach plummets even further. "You're saying…it's gonna kill me?"

"The Mark wants you as a demon. That means it has to stop your heart first. And I don't know how long it will take, but…yeah."

He hadn't been expecting her to break it to him gently, but she does at least seem a little sorry to say it. He closes his eyes and draws a deep breath, allowing that to sink in. Each heavy heartbeat in his chest seems like a taunt. "Right. Well, you're the doctor. So what can you do?"

He looks up at her again, almost hopeful, but she looks impassively back. "I don't know. Buy you more time, I guess. Maybe try some medication for the arrhythmias, but that tissue damage is gonna need surgery."

 _Just great._ He tastes bitterness on his tongue. After everything Sam went through to cure him, and now this. All he knows is that he can't go back to being _that_ again.

"I could do the surgery, if you wanted," she continues, oblivious to his reaction. "Done it plenty of times on demons. Just give me a week to get hold of a bypass machine, and I could…"

"I'm good, thanks," he cuts her off, his chest feeling tight. He doesn't know why he rejects it so certainly, though part of him is wondering if Cas could help. But with the angel's grace already running so low, Dean can't ask this of him.

"Medication, then." She turns to one of the trolleys, rifling through the bottles of medication on the bottom shelf, again ignoring the look of desperation on his face. He clenches his jaw, not really listening. "Here. Try this." He's jolted back to the present by the feeling of her pressing something to his lips, and a second later he realizes it's a pill. His mouth opens without thinking, and she pushes it in.

"Do I not get a glass of water?" he complains, tasting the real bitterness of it, and she just raises a mocking eyebrow.

"No. Now just swallow. Or is your gag reflex gonna be a problem?"

He scowls back, but does as he's told.

"Beta blockers. Let's see how that pans out," she says, turning her attention back to the monitor screen, and he finds himself following her gaze.

"You think that can help?"

"With the palpitations? Yeah. Should bring down your resting rate."

A couple of minutes pass, Dean's mind reeling, Carter just calmly watching the numbers on the monitor screen fall, then she gives a satisfied nod. "Sixty-nine. Good enough," she says, then smirks. "Alright. You can get dressed now." Her attention turns to finally unfastening the restraints, and he can't move to get up fast enough as she pulls the stickers off his chest and then frees his wrists. Fortunately, she seems to have no interest in watching while he puts his clothes back on, more concerned with tidying away her equipment.

When he's finally done and turns back to her, she's holding out a bottle of pills to him. "Here. Atenolol. Should last you between one month and three, depending on how often you get the palpitations. One a day, and one more if you feel an episode coming on. Go up to two a day if it doesn't help."

Somewhat warily, he accepts the bottle off her. "And how much are they gonna cost?"

She smirks again. "Let's call them free. It's not like I paid to get hold of them anyway."

He raises a cautious eyebrow at that. "And the consultation?"

Another smirk. "Let's call that free, too. Don't wanna clean you out on your first visit."

Whatever motive she has for that, he doesn't know, and he eyes her suspiciously. "You sure about that? Even with the…" He motions awkwardly towards her cheek, feeling another wave of shame.

"I'm sure. You were a pretty interesting case, actually. Save your money for the surgery."

"I'm not gonna have the surgery."

She shrugs. "Sure. But in case you change your mind…" She holds her hand out to him, a slip of paper gripped between her index and middle fingers. He guesses she wrote it while he was getting dressed. "Call ahead next time."

He briefly considers declining, considering how unpleasant the whole ordeal had been, but something compels him to reach out and take it. "Alright. Thanks, doc."

"No problem." She still has that goddamned smirk on her face, and he wishes he knew why.

"So, uh…I'll see myself out, then?"

"You do that." He can't tell if she's mocking him or not. "See you around, Winchester."

He just grunts gruffly and turns to walk away, unable to get out of there fast enough. He can feel her eyes burning into the back of his skull right until he turns the corner, and even then it feels like she's watching him right until he leaves the apartment. Still, he can't exactly call the whole thing a waste. The bad news is only slightly sweetened by the pill bottle resting in the inside pocket of his jacket, but it is hope, and in the end, it hadn't even cost.

Now he just has to get back to the bunker and hope Sam doesn't question where he's been.


End file.
